静息态下不同性别抑郁症患者脑功能及其差异的fMRI研究

目的:探讨静息态下不同性别抑郁症患者的脑功能特点及其差异.方法:男女抑郁患者各11例及性别、年龄、受教育程度均与患者匹配的健康对照22例参加静息态fMRI扫描.结果:男抑郁组较男对照组右额上回、双侧额中回、左楔前叶、右前扣带回背侧、左后扣带回、右海马旁回及右尾状核区域局部一致性增高(K值≥10,P＜0.005).女抑郁组较女对照组右额中回、左额下回、右后扣带回及左尾状核区域局部一致性增高(K≥10,P＜0.005).男抑郁组较女抑郁组左顶下小叶、右颞上回、右颞中回区域局部一致性增高(K≥10,P＜0.005),而女抑郁组未显示较男抑郁组局部一致性的增高;女对照组较男对照组左尾状核局部一致性增高(K≥10,P＜0.005),而男对照组未显示较女对照组局部一致性的增高.结论:进一步支持了既往提出的抑郁症存在的病理神经环路(边缘-皮层-纹状体-苍白球-丘脑)的假说,并认为静息态下抑郁症患者的脑功能具有性别差异.     

静息态下抑郁症患者脑功能与临床症状的相关性

目的: 探讨静息态下抑郁症患者脑局部一致性(regional homogeneity,ReHo)与抑郁症状群的关联.方法: 17名首发重性抑郁症患者与17名性别、年龄、教育程度相匹配的健康者参与了静息态功能磁共振(fMRI)的扫描.将患者的脑ReHo值与其抑郁症状群进行相关分析,设P<0.005,k值≥10为相关具有统计学意义.结果: 抑郁症患者以下症状群与脑区的相关具有统计学意义.焦虑与右前额中部、左脑岛ReHo值呈负相关(r=-0.85,-0.55;均P<0.001);认知障碍与左前额中部、右脑岛ReHo值负相关(r=-0.83,-0.67;P<0.01),而与右海马旁回ReHo值正相关(r=0.90;P<0.01);迟缓与左前额中部、右额下回、右尾状核ReHo值负相关(r=-0.66,-0.67,-0.55;均P<0.001),而与右前扣带回腹侧ReHo值呈正相关(r=0.80,P<0.001);睡眠障碍与左楔前叶、右脑岛ReHo值负相关(r=-0.72,-0.66;P<0.01);绝望感与左后扣带回ReHo值负相关(r=-0.84,P<0.001).结论: 本研究提示抑郁症患者的焦虑、认知障碍、迟缓、睡眠障碍及绝望感症状可能是部分特定的脑神经异常活动的表现.     

基于图卷积网络的MDD静息态功能磁共振功能连接性别差异研究

目的：利用图卷积网络（GCN）模型探究不同性别抑郁症（MDD）患者的功能连接差异,为实现MDD的精准诊治提供依据。方法：基于Rest-meta-MDD项目大样本多中心静息态功能磁共振数据,使用GCN模型分别对男性和女性样本进行独立训练,获得不同性别高鉴别脑区的拓扑特征及其与临床症状的相关性。结果：与支持向量机相比,GCN模型的平均分类准确率提高了5%以上。其中,男性组MDD和HC分类的平均准确率为77.91%,且右侧前额叶、右侧顶叶和左侧下顶叶的节点度与汉密尔顿焦虑量表得分呈显著正相关。女性组的平均准确率为79.71%,且右侧枕叶的节点介数与汉密尔顿抑郁量表得分呈显著负相关。结论：GCN提升了男性和女性MDD的分类准确率,提示男性MDD可能为焦虑型,而女性MDD则可能为抑郁型。     

患有抑郁症的自杀个体大脑功能连接异常：静息态功能性核磁共振成像的证据

自杀是一个重要的公共卫生问题,精神障碍是自杀最重要的风险因素,尤以抑郁症与自杀关系密切。本文综述了与抑郁症自杀相关的静息态功能性核磁共振成像脑功能连接异常的相关研究,发现主要存在于默认网络和突显网络的功能连接异常可能作为抑郁症患者自杀行为的神经标记物,从而为自杀的预测、诊断及干预提供一定的依据。     

抑郁症的静息态脑功能磁共振研究

本研究的目的是研究抑郁症患者与健康人静息态脑功能的差别。对符合DSM-IV诊断标准的53例抑郁症患者和38例正常对照进行静息态功能磁共振扫描,采用局部一致性(regional homogeneity,ReHo)的方法分析数据,然后进行基于体素的组间比较,分析其静息态脑功能的差异。结果显示与正常组相比,抑郁组在双侧前扣带皮质(anterior cingulate cortex,ACC)、左侧内侧前额叶皮质、左侧颞中回均有ReHo值降低。ACC位置ReHo值显著降低提示抑郁症患者在前扣带皮质及其相邻部位自发神经活动异常。     

正常脑老化中静息态功能磁共振成像功能连接的研究进展

【摘要】静息态功能磁共振成像（fMRI）作为一种不需要任务刺激就能呈现功能脑影像的技术手段,在临床上被广泛应 用。基于静息态fMRI的静息态功能连接（RSFC）,作为一种重要的计算机辅助分析法,能够度量不同脑区的脑功能连接 强度,对脑老化相关的神经科学领域的研究具有重要意义。本文介绍了功能连接的基本概念,总结了近年来脑老化相关 的人脑功能连接的研究成果,最后提出了该研究领域存在的问题及未来的研究方向。     

基于静息态功能磁共振图像的动态功能连接特征的智商预测

目的近年来越来越多的研究表明大脑不同脑区间的功能连接的动态波动具有生理意义,但关于智商(intelligence quotient,IQ)的相关研究较少。本文基于动态功能连接(dynamic functional connectivity,DFC)提取动态特征对智商进行评估,为智商预测探索新的特征参数和预测模型。方法基于97个儿童静息态功能磁共振图像(resting state functional magnetic resonance image,RS-fMRI),采用滑动窗相关计算方法构建DFC。基于DFC提取相应时域、频域特征,通过弹性网(elastic-net,E-Net)和最小角回归(least angle regression,LAR)算法建立智商回归模型进行个体智商预测,并通过置换检验验证其显著性。结果基于动态功能连接的特定频段(0.075~0.1 Hz)频域特征和波动均值特征,可以实现对智商的基本预测,且频域特征的表现优于时域特征。另外,基于LAR算法构建的预测模型的表现优于E-Net算法。结论个体脑功能连接随时间的动态波动足以预测个体智商,且特定频段的频域特征和LAR算法能够提高预测准确率,这可为个体智商评估研究和动态功能连接的应用提供新的思路。     

作曲家大脑的静息态脑功能网络研究

音乐家大脑是认识大脑可塑性机制的天然模型,也是脑影像科学关注的重点研究对象之一。但是,目前针对音乐家的研究,包括对音乐创作方面的脑机制研究,仍以钢琴演奏家为主要研究对象。鉴于创作与表演是两个不同阶段且存在巨大差异,仅以钢琴演奏家作为研究对象对音乐家脑机制的研究是不完整的。专业作曲家是一类特殊的音乐家,他们经历过长期的音乐训练,能够在创造性思维的引领下,结合情感等要素来进行音乐素材的组织。用功能磁共振(fMRI)采集29名作曲家在作曲任务前后的大脑静息态影像,利用独立成分分析方法分离出其脑功能网络中常见的13个成分。采用配对t检验,对比分析作曲前后这些成分的变化。结果发现,在完成作曲任务后,以下脑功能网络连接显著减弱,包括听觉网络(AN)与右侧额顶网络(RFPN)、感觉运动网络(SMN)与突显网络(SN);同时也发现在完成作曲任务后,以下脑功能网络连接显著增强,包括自我参照网络(SRN)与视觉I区网络(VN1)、自我参照网络(SRN)与视觉II区网络(VN2)、默认模式网络(DMN)与视觉I区网络(VN1)。这些结果证明,感觉、认知加工等与视觉区域的协调整合在作曲过程中的重要性,对推动音乐家大脑可塑性的认识和音乐创作的脑机制研究均十分有意义。     

慢性失眠患者大脑蓝斑的异常静息态功能连接

目的:利用功能连接方法观察慢性失眠患者静息态下蓝斑的异常功能连接。方法:采集49例慢性失眠患者以及47例性别年龄和受教育程度相匹配的健康对照组的功能磁共振图像,以蓝斑为感兴趣区域,与全脑其他体素进行功能连接分析,得到两组之间功能连接的差异脑区,再对异常连接脑区的功能连接值与临床量表分数做相关分析。结果:与对照组相比,慢性失眠患者蓝斑与右楔前叶皮质、右后扣带回皮质、左颞中回皮质、左距状沟周围皮质、右眶部额上回皮质之间的功能连接增强（P<0.05, FDR校正）,并且蓝斑与左颞中回皮质之间功能连接值与抑郁自评量表呈正相关（P=0.021）。结论:慢性失眠患者蓝斑与多个脑区（主要是默认模式网络）出现的异常功能连接,可能有助于更好地理解慢性失眠的神经生物学机制,可能为失眠的高度唤醒假说提供新的影像学证据。     

癫痫患者默认网络的静息态功能磁共振成像研究

目的:分析癫痫患者静息态fMRI下默认网络及其潜在结构的变化.方法:对15名临床诊断为原发全身强直痉挛癫痫患者和20名正常志愿者静息态时的fMRI数据进行独立成分分析,依据空间最佳匹配原则挑选独立成分,研究正常被试和癫痫患者的默认网络差异,并选定默认网络中11个脑区构建功能连接网络,运用图论和聚类方法探讨其潜在结构的改变.结果:与正常对照组相比,患者组默认网络的脑区激活普遍下降,功能连接网络发生明显变化,且整个网络呈现出混乱的层次化结构.结论:静息态下癫痫患者的默认网络及潜在的层次化结构发生异常.     

Functional connectivity in fronto-subcortical circuitry during the resting state in obsessive-compulsive disorder

Obsessions and compulsions mediated by cognitive inflexibility might be associated with abnormal resting state functional connectivity in the default mode network (DMN) that represents intrinsically generated neuronal activity. It was hypothesized that decreased functional connectivity in the DMN would occur in components of fronto-subcortical circuits in patients with obsessive-compulsive disorder (OCD). Twenty-two unmedicated OCD patients and 22 age- and sex-matched healthy controls received resting state functional scanning runs. The posterior cingulate cortex (PCC) region was chosen as the seed region for the connectivity analysis. Correlations between temporal connectivity with the seed region and scores on clinical measures and obsessive-compulsive symptom dimensions were also assessed. OCD patients demonstrated less functional connectivity within the DMN in the anterior cingulate cortex, middle frontal gyrus, and putamen compared to controls. The functional connectivity to the PCC seed region in OCD patients was in the direction opposite to that in the prefrontal areas with regard to scores on cleaning and obsessions/checking dimensions of OCD. These data provide evidence for fronto-subcortical dysfunction in OCD. Results from this study also support the notion that OCD is a heterogeneous disorder mediated by distinct circuits.     

Aging influence on functional connectivity of the motor network in the resting state

We used functional MRI (fMRI) to study the aging influence on functional connectivity of the motor network in the resting state. A network model based on graph theory was used to measure functional connectivity. The total connectivity degree of each region within the motor network was calculated and compared between aged and young groups. We found that the pattern of functional connectivity was changed in aged subjects, including a significant decrease in the functional connectivity degree of the right cingulate motor area and left premotor area compared to young subjects. Our study demonstrates that normal aging modulates the functional connectivity of motor network in the resting state. We postulate that this abnormal functional connectivity of motor network in the baseline state is an important reason contributing to the deteriorated motor ability in aged subjects.     

Changes of functional connectivity of the motor network in the resting state in Parkinson's disease

We used functional MRI (fMRI) and a network model based on graph theory to measure functional connectivity of brain motor network in the resting state in patients with Parkinson's disease (PD). FMRIs were acquired in 22 PD patients before and after levodopa administration, and in age- and sex-matched normal controls. The total connectivity degree of each region within the motor network was calculated and compared between patients and controls. We found that PD patients at off state had significantly decreased functional connectivity in the supplementary motor area, left dorsal lateral prefrontal cortex and left putamen, and had increased functional connectivity in the left cerebellum, left primary motor cortex, and left parietal cortex compared to normal subjects. Administration of levodopa relatively normalized the pattern of functional connectivity in PD patients. The functional connectivity in most of regions in the motor network correlated with the Unified Parkinson's Disease Rating Scale motor score in the patients. Our findings demonstrate that the pattern of functional connectivity of the motor network in the resting state is disrupted in PD. This change is secondary to dopamine deficiency, and related to the severity of the disease. We postulate that this abnormal functional connectivity of motor network in the baseline state is possibly an important factor contributing to some motor deficits in PD, e.g. akinesia.     

Intrinsically organized network for face perception during the resting state

We investigated 0.01–0.08 Hz low-frequency fluctuations of BOLD-fMRI signals in the face and object-responsive regions during the resting-state and during face or object viewing tasks. By comparing the effects of the face-responsive regions of interest with those of the object-responsive regions of interest, we observed a distributed cortical network of face perception during the resting-state among posterior fusiform gyrus, inferior occipital gyrus, and superior temporal sulcus. This network was also significantly activated during the face perception task. The face perception task also activated additional areas in the frontal and parietal regions. Our results suggest that the “core” but not the “extended” network for face processing is already in some form of activation during the resting-state. A possible function of the resting-state face perception network is perhaps to prepare the brain to process faces that individuals are highly likely to encounter in their environment.     

Functional connectivity in the pontomedullary respiratory network

Current models propose that a neuronal network in the ventrolateral medulla generates the basic respiratory rhythm and that this ventrolateral respiratory column (VRC) is profoundly influenced by the neurons of the pontine respiratory group (PRG). However, functional connectivity among PRG and VRC neurons is poorly understood. This study addressed four model-based hypotheses: 1) the respiratory modulation of PRG neuron populations reflects paucisynaptic actions of multiple VRC populations; 2) functional connections among PRG neurons shape and coordinate their respiratory-modulated activities; 3) the PRG acts on multiple VRC populations, contributing to phase-switching; and 4) neurons with no respiratory modulation located in close proximity to the VRC and PRG have widely distributed actions on respiratory-modulated cells. Two arrays of microelectrodes with individual depth adjustment were used to record sets of spike trains from a total of 145 PRG and 282 VRC neurons in 10 decerebrate, vagotomized, neuromuscularly blocked, ventilated cats. Data were evaluated for respiratory modulation with respect to efferent phrenic motoneuron activity and short-timescale correlations indicative of paucisynaptic functional connectivity using cross-correlation analysis and the "gravity" method. Correlogram features were found for 109 (3%) of the 3,218 pairs composed of a PRG and a VRC neuron, 126 (12%) of the 1,043 PRG–PRG pairs, and 319 (7%) of the 4,340 VRC–VRC neuron pairs evaluated. Correlation linkage maps generated for the data support our four motivating hypotheses and suggest network mechanisms for proposed modulatory functions of the PRG.     

基于静息状态的功能磁共振成像

基于静息状态的功能磁共振成像已经成为当前人脑功能研究的重要手段之一.本文首先介绍了基于静息状态功能磁共振成像人脑功能研究的历史和现状,包括对正常人脑功能的研究和对病理状态下的人脑功能异常研究.然后介绍了基于静息状态功能磁共振成像的两种主要的数据分析方法:功能连接分析和慢波振荡特性分析.     

Functional connectivity in the cognitive control network and the default mode network in late-life depression

BackgroundAbnormalities have been identified in the Cognitive Control Network (CCN) and the Default Mode Network (DMN) during episodes of late-life depression. This study examined whether functional connectivity at rest (FC) within these networks characterizes late-life depression and predicts antidepressant response.Methods26 non-demented, non-MCI older adults were studied. Of these, 16 had major depression and 10 had no psychopathology. Depressed patients were treated with escitalopram (target dose 20 mg) for 12 weeks after a 2-week placebo phase. Resting state time series was determined prior to treatment. FC within the CCN was determined by placing seeds in the dACC and the DLPFC bilaterally. FC within the DMN was assessed from a seed placed in the posterior cingulate.ResultsLow resting FC within the CCN and high resting FC within the DMN distinguished depressed from normal elderly subjects. Beyond this “double dissociation”, low resting FC within the CCN predicted low remission rate and persistence of depressive symptoms and signs, apathy, and dysexecutive behavior after treatment with escitalopram. In contrast, resting FC within the DMN was correlated with pessimism but did not predict treatment response.ConclusionsIf confirmed, these findings may serve as a signature of the brain's functional topography characterizing late-life depression and sustaining its symptoms. By identifying the network abnormalities underlying biologically meaningful characteristics (apathy, dysexecutive behavior, pessimism) and sustaining late-life depression, these findings can provide a novel target on which new somatic and psychosocial treatments can be tested.     

Spontaneous BOLD event triggered averages for estimating functional connectivity at resting state

Recent neuroimaging studies have demonstrated that the spontaneous brain activity reflects, to a large extent, the same activation patterns measured in response to cognitive and behavioral tasks. This correspondence between activation and rest has been explored with a large repertoire of computational methods, ranging from analysis of pairwise interactions between areas of the brain to the global brain networks yielded by independent component analysis. In this paper we describe an alternative method based on the averaging of the BOLD signal at a region of interest (target) triggered by spontaneous increments in activity at another brain area (seed). The resting BOLD event triggered averages ("rBeta") can be used to estimate functional connectivity at resting state. Using two simple examples, here we illustrate how the analysis of the average response triggered by spontaneous increases/decreases in the BOLD signal is sufficient to capture the aforementioned correspondence in a variety of circumstances. The computation of the non linear response during rest here described allows for a direct comparison with results obtained during task performance, providing an alternative measure of functional interaction between brain areas.     

Changes in resting connectivity during recovery from severe traumatic brain injury

In the present study we investigate neural network changes after moderate and severe traumatic brain injury (TBI) through the use of resting state functional connectivity (RSFC) methods. Using blood oxygen level dependent functional MRI, we examined RSFC at 3 and 6 months following resolution of posttraumatic amnesia. The goal of this study was to examine how regional off-task connectivity changes during a critical period of recovery from significant neurological disruption. This was achieved by examining regional changes in the intrinsic, or “resting”, BOLD fMRI signal in separate networks: 1) regions linked to goal-directed (or external-state) networks and 2) default mode (or internal-state) networks. Findings here demonstrate significantly increased resting connectivity internal-state networks in the TBI sample during the first 6 months following recovery. The most consistent finding was increased connectivity in both internal and external state networks to the insula and medial temporal regions during recovery. These findings were dissociable from repeat measurements in a matched healthy control sample.